1. .ssh directory permissions to be 700 (drwx------)
2. public key (.pub file) to be 644 (-rw-r--r--)
3. private key (id_rsa) should be 600 (-rw-------)
4. Lastly, your home directory should not be writeable by the group or others (at most 755 (drwxr-xr-x)).
chmod 700 ~/.ssh
chmod 644 ~/.ssh/id_rsa.pub